1. Field of the Invention
This invention relates to an apparatus and process for simulating field fluid flow conditions under elevated temperature and pressure for evaluation of precipitation, corrosion, and other fluid-solid reactions. The system of this invention may be used to study problems encountered in gas and oil production, refining, cooling towers, desalination and to evaluate chemicals for their effectiveness in reduction of these problems.
2. Description of Related Art
Electronically controlled proportioning pumps for varied mixing of a plurality of liquids providing a smooth composition gradient in the output flow of uniform velocity and pressure are taught by U.S. Pat. No. 4,714,545. The output flow may pass through a sample injection valve and combined output flow with sample delivered to an analytical instrument, such as a chromatograph.
There are a wide variety of systems for sensing and adding desired chemical in a bypass line of a flowing liquid: U.S. Pat. No. 4,945,939 teaches a computerized pH control system to control the pH in a reservoir system by monitoring a side recirculating stream for pH changes from preset tolerance and injecting pH affecting liquid in the side stream downstream from the monitoring tap for passage to the reservoir; U.S. Pat. No. 4,306,581 teaches a chemical concentration control system for a fluid circulator having an independent diverter and chemical addition line downstream from the circulator and returning to the fluid reservoir and within the diverter line a flow-through conductivity cell continuously monitors the chemical composition and at a preset value activates a solenoid valve allowing concentrated chemical to be aspirated into the line and passed to the solution tank until the desired concentration is restored and the solenoid valve deactivated and closed; A computer controlled system for introduction of chemicals into a water treatment system taught by U.S. Pat. No. 4,648,043 has a shunt line having a first sensor, a downstream injector for adding a second fluid, and a downstream second sensor, the sensors signalling a computer which controls the injector in accordance with preset parameters.
U.S. Pat. No. 4,460,008 teaches a cooling water tower control system which senses tower water and make-up water conductivity and utilizes these readings to establish an indexing factor for adjusting the trip point.
U.S. Pat. No. 4,705,503 teaches a catheter having an internal metabolite sensor downstream from a semipermeable region where dynamic equilibrium is attained between in-vivo external metabolite and higher concentration metabolite in the infusate. Changing metabolite concentration controls a chemical valve providing codelivery of a drug.
U.S. Pat. No. 5,034,190 teaches an apparatus and process for accelerated corrosion testing of nickel alloys by subjecting a mechanically stressed sample to a high temperature mixture of steam and hydrogen. Hydrogen is injected into the pressurized vessel through a selective hydrogen permeable membrane.
U.S. Pat. No. 4,863,571 teaches simulating and electrochemically determining corrosive behavior of an electrical conducting element embedded in a polymer by using the element as a working electrode of an electrochemical cell having a viscous electrolyte containing at least one corrosive substance. The electrode may be pretreated with a corrosion inhibitor to evaluate that inhibitor.
Submersible pump flow simulations for CaCO.sub.3 scaling and effectiveness of scale inhibitors therefore has been described in J. E. Oddo, J. P. Smith, and M. B. Tomson, Analysis of and Solutions to the CaCO.sub.3 and CaSO.sub.4 Scaling Problems Encountered in Wells Offshore Indonesia, SPE 22782, Soc. Petr. Engr. 66th Ann. Tech. Conf., Dallas, Tex., (Oct. 6-9, 1991). The simulations described were only CaCO.sub.3 scalings which were achieved by raising the temperature and monitored by pH change. Simulations were restricted to certain carbonate chemistries because in most instances carbonate scaling would occur in the container without inhibitor before the test began. Sulfate scales could not be detected by the apparatus shown in this article since they do not cause a pH change in water under most desired conditions of simulation.